I had the same problem with my 46 pickup/261, low water pump. The water pump is so low the fan will hit the bottom hose connection to the radiator. I was able to elongate the radiator mounting holes and slide the radiator down almost an inch. Still had to whittle down the aluminum, shallow flex fan from NAPA. Ultimate solution was to ad an electric fan with a toggle switch out front, which works great.
If and when I add an AC system, will go to a puller style fan and remove the fan on the water pump altogether. Also a shroud may help, have one off a 2 ton truck from the factory. Next hood I do is getting louvers also.
Some discussion of temp problems came up at Lodi. One tip I saw on a JIMMY, was to install a 'T' on the head where the temp sender goes and run a small hose back to the thermostat housing to improve water circulation. A great way to know for sure whats happening temp wise is to pick up an infra red temp gun.
